Lignins provide anti-oxidant benefits and can act as a surface deposition aid in consumer goods products, such as skin treatment compositions, hair treatment compositions, oral care compositions home care compositions and detergent compositions (especially hand wash detergents). In addition, for home care applications, lignins can also provide surface modification benefits which lead to improved shine and water repellence benefits.
However, lignins are difficult to incorporate in consumer goods products due to their poor solubility in water. In addition, many lignins, such as Kraft lignin, comprise sulphur, which leads to poor chemical compatibility with other ingredients that may be present in consumer goods products, such as transition metals. Sulphur may also cause malodour problems.
Multi-functionalisation of sulphur containing lignin is taught by U.S. Pat. No. 8,075,637. However, multi functionalisation of small lignin oligomer molecules can lead to a poor water-solubility. The inventors have found that specific functionalisation by a predominantly single type of functional group provides a lignin oligomer that exhibits good solubility in water. In addition, specific functionalisation by a predominantly single type of functional group can also enable a higher loading of the functional group onto the lignin oligomer. This is especially important because of the relatively low molecular weight of the lignin oligomer.